765
FXUS65 KBYZ 191017
AFDBYZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
417 AM MDT TUE MAY 19 2026
KEY MESSAGES
- FROST/FREEZE CONDITIONS THIS MORNING.
- PATCHY FREEZING FOG POSSIBLE OVER THE PLAINS OF EASTERN MONTANA
THIS MORNING (UP TO A 20 PERCENT CHANCE).
- WEATHER SYSTEM BRINGS THE CHANCE OF PRECIPITATION TO THE AREA
WEDNESDAY INTO THURSDAY (40 TO 90 PERCENT, GREATEST OVER SOUTH-
CENTRAL MONTANA AND NORTH-CENTRAL WYOMING).
- MODERATE CHANCE OF SEEING AT LEAST 0.50 INCHES OF LIQUID
PRECIPITATION OVER SOUTH-CENTRAL MONTANA AND NORTH-CENTRAL
WYOMING WEDNESDAY INTO THURSDAY. SNOW LEVELS AS LOW AS 6 KFT.
SNOW ACCUMULATIONS POSSIBLE IN THE HIGH COUNTRY (MODERATE TO
HIGH CHANCE OF 4+ INCHES OF SNOW).
- WARMER BUT STILL UNSETTLED WEATHER CONTINUES INTO THE WEEKEND.
UPDATE
TEMPERATURES HAVE DROPPED INTO THE 20S TO LOWER 30S FOR MANY AREAS
EARLY THIS MORNING AS SKIES HAVE CLEARED OUT. WHILE NOT EVIDENT ON
SATELLITE OR WEBCAM IMAGES OVER THE AREA, PATCHY FOG REMAINS
POSSIBLE FOR EASTERN VALLEYS INTO THIS MORNING. HAVE NUDGED
TEMPERATURES DOWN A BIT FOR PLACES TO ACCOUNT FOR LATEST
OBSERVATIONS AND TRENDS. AFTER A COOL MORNING, LOOK FOR
TEMPERATURES TO REBOUND INTO THE UPPER 50S TO 60S TODAY. STP
DISCUSSION
TODAY THROUGH MONDAY...
THIS MORNING WILL BE COLD WITH TEMPERATURES IN THE MID 20S TO
LOWER 30S UNDER MOSTLY CLEAR SKIES. OVER THE PLAINS OF EASTERN
MONTANA, PATCHY FREEZING FOG IS ALSO POSSIBLE (UP TO 20 PERCENT
CHANCE), MAINLY WHERE PRECIPITATION RECENTLY OCCURRED. ANY FOG
THAT DOES DEVELOP WILL LIFT AFTER SUNRISE. WHILE MOSTLY DRY
CONDITIONS WILL PREVAIL AS TEMPERATURES WARM INTO THE 50S AND 60S
DURING THE DAY TODAY, A FEW LIGHT SHOWERS ARE POSSIBLE OVER SOUTH-
CENTRAL MONTANA DURING THE AFTERNOON AND EVENING (~15 PERCENT
CHANCE). WITH THIS, DRY AIR NEAR THE SURFACE WILL LIKELY FAVOR
VIRGA OVER PRECIPITATION MAKING IT TO THE GROUND, BUT OCCASIONAL
SPRINKLES MAY OCCUR. THE DRY AIR NEAR THE SURFACE MAY ALSO RESULT
IN BRIEF ERRATIC WINDS WITH GUSTS AROUND 30 MPH.
WEDNESDAY INTO THURSDAY, A WEATHER SYSTEM WILL BRING THE CHANCE
OF PRECIPITATION AND A BRIEF COOLDOWN BACK TO THE AREA. AHEAD OF
THE COLD FRONT ASSOCIATED WITH THIS WEATHER SYSTEM, ISOLATED TO
SCATTERED SHOWERS AND WEAK THUNDERSTORMS ARE FORECAST DURING THE
AFTERNOON AND EVENING ON WEDNESDAY. WITH THIS ACTIVITY, THE MAIN
THREAT INITIALLY LOOKS TO BE SOME ERRATIC WIND GUSTS (UP TO 40
MPH) WITH DRY AIR NEAR THE SURFACE BEFORE THE BETTER ATMOSPHERIC
MOISTURE MOVES IN TRANSITIONING THE THREAT TO MORE MODERATE TO
HEAVY RAIN. THE COLD FRONT WILL THEN DROP THROUGH THE AREA FROM
NORTH TO SOUTH LATE WEDNESDAY, TURNING WINDS OUT OF THE NORTH TO
NORTHEAST. AS THIS OCCURS, MODELED ATMOSPHERIC SOUNDINGS SUGGEST
THE ATMOSPHERE WILL SATURATE. THIS WOULD ALLOW MORE WIDESPREAD
LIGHT TO MODERATE PRECIPITATION TO DEVELOP OVER AND NEAR THE
MOUNTAINS AND FOOTHILLS LATE WEDNESDAY INTO THURSDAY. AS THE MAIN
TROUGH ASSOCIATED WITH THIS WEATHER SYSTEM SLIDES EAST THURSDAY,
THE CHANCE OF PRECIPITATION THEN SHIFTS EAST AND OUT OF THE AREA
BY LATE THURSDAY INTO EARLY FRIDAY. WHEN ALL IS SAID AND DONE, THE
CHANCE OF SEEING A HALF AN INCH (0.50") OF LIQUID PRECIPITATION
OR MORE IS 50 TO 75 PERCENT OVER AND NEAR THE MOUNTAINS AND
FOOTHILLS IN SOUTH-CENTRAL MONTANA AND NORTH-CENTRAL WYOMING. THE
CHANCE OF SEEING A HALF INCH OR MORE OF PRECIPITATION THEN
DECREASES AWAY FROM THE FOOTHILLS WITH THERE ONLY BEING A 10
PERCENT CHANCE BY BROADUS TO MILES CITY.
AS MENTIONED ABOVE, THE MID-WEEK WEATHER SYSTEM WILL BRING A
BRIEF COOLDOWN BACK TO THE AREA. WITH THIS, HIGH TEMPERATURES ON
THURSDAY ARE FORECAST IN THE 50S AND 60S AFTER SEEING 60S AND 70S
WEDNESDAY. THIS WILL ALLOW SNOW LEVELS TO START OUT AROUND 8000
FEET BEFORE DROPPING NEAR 6000 TO 6500 FEET BY THURSDAY.
SUBSEQUENTLY, MAINLY SNOW IS FORECAST IN THE MOUNTAINS WITH THIS
EVENT, WITH RAIN OVER THE LOWER ELEVATIONS. IT IS NOT OUT OF THE
QUESTION THAT SOME OF THE IMMEDIATE FOOTHILL LOCATIONS NEAR 6000
FEET IN ELEVATION SEE SOME SNOW THOUGH (MODERATE CHANCE). AS FAR
AS POTENTIAL SNOW AMOUNTS GO IN THE MOUNTAINS, THE CURRENT CHANCE
OF SEEING 6 OR MORE INCHES IS MODERATE TO HIGH, GREATEST OVER THE
NORTHERLY SLOPES OF THE ABSAROKA-BEARTOOTH MOUNTAINS.
FRIDAY INTO EARLY NEXT WEEK, TEMPERATURES LOOK TO GRADUALLY WARM
BACK ABOVE NORMAL WITH MAINLY NORTHWESTERLY TO WESTERLY FLOW
ALOFT. WITH THIS, ADDITIONAL WAVES OF ENERGY MAY WORK THROUGH THE
FLOW, BRINGING OCCASIONAL CHANCES OF PRECIPITATION. ARENDS
AVIATION
PATCHY FOG (20% CHANCE) IS POSSIBLE INTO THE MORNING HOURS OVER
PORTIONS OF THE CENTRAL AND EASTERN VALLEYS WITH VCFG AT KMLS AND
KSHR. OTHERWISE, EXPECT MAINLY VFR CONDITIONS TO PREVAIL
THROUGH THE PERIOD. A WEAK DISTURBANCE MOVING IN FROM THE WEST
WILL BRING ISOLATED SHOWERS TO WESTERN AND CENTRAL AREAS,
INCLUDING KLVM AND KBIL DURING THE AFTERNOON AND EVENING HOURS.
GUSTY AND ERRATIC WINDS UP TO 30 KTS ARE POSSIBLE WITH THE
SHOWERS. STP
PRELIMINARY POINT TEMP/POPS
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 065 042/070 044/059 040/071 045/080 050/083 052/087
1/U 13/T 86/W 10/B 00/U 10/U 01/B
LVM 060 036/064 037/056 035/069 040/076 044/080 047/082
2/W 25/T 97/W 01/B 00/U 11/U 01/N
HDN 066 036/072 042/059 037/073 041/079 046/084 049/087
1/U 12/T 67/W 11/B 00/U 10/U 00/U
MLS 064 040/073 044/063 040/070 043/079 048/083 050/086
0/U 11/B 53/W 11/B 00/U 10/U 00/U
4BQ 062 039/072 042/061 039/068 042/077 048/082 051/087
0/U 00/B 25/W 41/B 00/U 10/U 00/U
BHK 059 036/073 039/064 037/068 041/076 047/082 049/087
0/U 00/B 35/W 42/W 10/U 10/U 00/U
SHR 059 031/066 036/052 032/066 036/075 041/080 043/085
0/U 01/B 39/W 42/W 01/U 11/U 00/U
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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